This invention relates to valve assemblies and in a particular but not exclusive aspect to valve assemblies for use with swimming pool cleaning systems particularly cleaning systems of the type in which a vacuum head automatically traverses the pool.
It is usually desirable to control and regulate the amount of suction to an automatic pool cleaner. If there is insufficient suction, the cleaner will operate slowly or not at all and if there is too much suction, the cleaner is subject to premature wear and may clamp down and stick to the pool surfaces. Further the cleaner hose may also collapse if suction is excessive.
There are gradual and sharp changes in negative pressure (suction) with all automatic pool cleaners of this type. Gradual changes include load changes as the cleaner moves about, E and changes depth in the normal course of operation and suction decreases as the filter and leaf baskets associated with the system fill with debris. Sharper changes are caused by spikes that are inherent in the design of many cleaners caused by quickly and repeatedly opening and closing the water flow which propels the cleaner. There may also be a sharp rise in negative pressure caused by a blockage at the cleaner.
In some systems, the hose of a pool cleaner interferes with the function of the weir door of the skimmer box. The purpose of the weir door is to isolate the interior of the skimmer box from the body of water in the pool and prevent debris reentering the pool. When however a vacuum cleaner hose is connected via a weir door, debris collected in the weir can pass back into the pool.
U.S. Pat. No. 5,570,713 describes a valve and a method of operating a valve which has an inlet, an outlet, a bypass inlet and a pivoting cover mechanism for controlling the cover in order to provide a relief through the valve. The valve described in U.S. Pat. No. 5,570,713 is its designed for use with a swimming pool vacuum and skimming system similar to that described in another U.S. Pat. No. 5,581.826. The systems described in the aforementioned U.S. patents are now common and the function of vacuuming a pool and skimming the surface of the pool water can be carried out independently or simultaneously. The arrangements disclosed in the above patents however do not overcome all of the abovementioned disadvantages.
The present invention aims to overcome or alleviate one or more of the above disadvantages by providing in one aspect an improved valve assembly which has particular but not exclusive application to use with swimming pool cleaners which operates efficiently, which will easily fit an existing system and which will compensate automatically for changes in suction pressure to the cleaner and which also may be used in such a manner that skimming of the pool may continue whilst a pool cleaner is operating. The present invention in a filer aspect aims to provide an improved valve assembly which may be used in other applications not limited to swimming pool applications. Other objects and advantages of the present invention will become apparent from the following description.
According to a first aspect of the present invention, there is provided a valve assembly for pool cleaning apparatus, said valve assembly being arranged in use in the suction line of said pool cleaning apparatus and including a main body defining a main flow passage, an inlet to the main flow passage for connection to said pool cleaning apparatus and an outlet from the main flow passage for connection to the suction line and a branch body extending from said main body and defining a branch passage communicating with said main flow passage, said branch passage terminating in an inlet opening, valve flap means mounted to said branch body for pivotal movement between a closed position closing said branch passage and an open position in which liquid flows from said inlet opening and through said branch passage into said main flow passage., and spring biasing means disposed substantially within said branch body and biasing said valve flap means towards said closed position, said biasing means having a first end acting on the side of said valve flap means opposite said inlet opening and a second end acting against said branch body rearwardly of said valve flap means whereby said biasing means does not impede flow through said branch passage upon opening of said valve flap means, said biasing means permitting said valve flap means to pivot between said open position and said closed position in response to suction pressure requirements of said pool cleaning apparatus.
The biasing means suitably controls the opening of the valve flap means so that the extent that the flap means opens is in direct proportion to changes in pressures requirements of the pool cleaning apparatus.
Preferably, the branch body includes opposite side walls and the valve flap means is pivotally mounted to the opposite side walls via pivot axle means. Suitably the biasing means comprises a coil spring around the axle means, said coil spring terminating in first and second legs, the first leg acting against the valve flap means and the second leg acting against the branch body.
Preferably, the pivot axle means comprises a pair of opposite axles and the biasing means includes a pair of coil springs around respective axles. Suitably the springs are integrally formed and the first legs thereof comprise a common U-shaped leg. Preferably, the axles are formed integrally with valve flap means.
Preferably, the opposite side walls of the branch body have sockets for receiving the axle means, the sockets having a restricted entry portion which enables the axle means to be moved into and out of the sockets only in one attitude of the axle means. The sockets are suitably of part circular form being complementary to a bearing surface of the axles. Alternatively, the flap means may be supported by a separate axle or axles supported by opposite walls of the branch body and a single coil spring arrangement provided centrally of the flap means.
In a further form, the biasing means comprises a leaf spring having a first and second legs acting against the rear of the valve flap means and branch body respectively.
Suitably, the branch body includes a top wall extending between the side walls, the flap means being pivotally mounted to the side walls adjacent the top wall and the second end of the biasing means acting against an inner surface of the top wall. Suitably, also, the branch body includes a lower wall extending between the side walls and the distance between the pivot axle means and a distal edge of the valve flap means is predetermined so that the valve flap means is restrained from pivoting in an outward direction beyond its closed position by contact with the lower wall. Alternatively, stop means may be provided to limit movement of the valve flap means outwardly of the branch passage. Such means may comprise an abutment on a wall of the branch passage. In this configuration, the valve flap means in the closed position may be inclined inwardly or substantially at right angles to the branch passage.
In yet a further arrangement, the biasing means may comprise a coil spring having one end acting on the rear of the valve flap means and the other end received in a housing comprising an extension of the branch body.
Most preferably, the branch body extends from the body substantially at right angles. This allows the branch passage to be located adjacent the outlet of the main flow passage and thus the inlet opening to the branch passage to be positioned adjacent to the vacuum plate which will minimize the risks of a vortex being created in use and air being drawn into the pool pump.
The inlet to the valve assembly body may comprise an elbow. The valve inlet can be arranged to accommodate male hose ends and a tapered adapter accessory so that the valve inlet may accommodate hose ends of differing sizes and configurations.
The valve flap means may comprise a single flap or alternatively a pair of flaps which may be substantially coplanar in the closed position or which form a dihedral in the closed position. Alternatively, one flap may overlap the other flap in the closed position. The flaps however are suitably arranged to operate independently. In one arrangement, the biasing means for one flap is greater than that of the other flap so that one opens and closes ahead of the other. This may also be achieved by having the flaps of different sizes. The respective flaps may have complementary end portions which cooperate in the closed position of the valve flap means. Alternatively, the respective flaps may be in an end to end relationship in the closed position of the valve flap means. Stop means may provided to limit outward movement of the flaps or respective flaps.
According to another aspect of the present invention there is provided a method of vacuuming a swimming pool of the type having a skier box and vacuum plate within the skimmer box while simultaneously skimming the surface of the body of water within the pool, the method including the steps of engaging the outlet of the main body of the valve assembly of the above described type with the vacuum plate of a pool skimmer box and connecting a vacuum cleaner hose to said valve assembly.
In operation, the valve flap means opens up to maximum by-pass to maintain water supply to the pool and prevent the pool pump from burnout and also enables skimming of the water of debris while using the automatic pool cleaner. In the valve assembly of the invention, the greater the suction applied by the pump, the more the valve flap means opens proportionately increasing the skimming function of the cleaning system. The lower the suction, the more the valve closes diverting needed suction to operate the in-pool cleaner efficiently. A further